1. IPv6 concepts and terminology

While some IPv6 concepts and terminology are similar to those
for IPv4, others are quite different. The following list is a brief
summary of some of the important IPv6 terminology you should be
familiar with to begin developing an IPv6 migration plan for your
organization. Figure 1
illustrates how many of these concepts are interrelated. Additional
IPv6 terminology is introduced later in this lesson when
appropriate.

Node A device that can be
configured with an IPv6 address. Examples of nodes include hosts
and routers.

Host A node that can be
either the source of or a destination for IPv6 traffic. Hosts are
not able to forward IPv6 packets that are explicitly addressed to
them. Instead, they silently discard such packets.

Router A node that is able to
forward IPv6 packets not explicitly addressed to itself. Routers
advertise their presence on a network. They also advertise host
configuration information.

Link A collection of network
interfaces that use the same 64-bit IPv6 unicast address prefix
and which includes hosts but not routers. Links are bounded by
routers and are also referred to as network
segments or subnets.

Interface A representation
for how a node is attached to a link. An interface can be either
of the following:

Physical For example, a
network adapter in a server.

Logical For example, a
tunnel interface that encapsulates IPv6 packets inside an IPv4
header to send IPv6 traffic over an IPv4-only network.

Address An identifier that
designates either the source or destination of an IPv6 packet.
IPv6 addresses are assigned at the IPv6 layer of an interface. The
different types of IPv6 addresses are described later in this
lesson.

Neighbors Nodes connected to
the same link. In IPv6, neighbors are able to detect and monitor
reachability with one another by using a process called Neighbor
Discovery.

Network Two or more links
connected together by routers.

Site An autonomously operated
IPv6 network that is connected to the IPv6 Internet.

Figure 1. Basic IPv6 networking concepts.

IPv6 and the TCP/IP protocol architecture

As Figure 2
illustrates, the TCP/IP protocol networking stack on the Microsoft
Windows platform is implemented using a dual IP layer approach. This
means for example that

Only a single implementation of transport layer protocols
such as Transmission Control Protocol (TCP) or User Datagram
Protocol (UDP) is needed for both IPv4 and IPv6
communications.

Only a single implementation of framing layer
protocols—such as Ethernet (802.3), Point-to-Point Protocol
(PPP), and mobile broadband (802.11)—is needed for both IPv4 and
IPv6 communications.

This dual IP layer TCP/IP stack is implemented on the
following Windows platforms:

Windows 8

Windows 7

Windows Vista

Windows Server 2012

Windows Server 2008 R2

Windows Server 2008

Figure 2. The dual IP layer TCP/IP protocol stack.

Note

IPv6 on Windows platforms

Because IPv6 functionality is essentially the same on
Windows 8, Windows 7, Windows Vista, Windows Server 2012, Windows
Server 2008 R2, and Windows Server 2008, all information presented
in the remainder of this lesson applies to these specific Windows
platforms unless explicitly stated otherwise. IPv6 functionality
in earlier Windows platforms, such as Windows XP and Windows 2003,
is more limited and therefore is not covered in this
lesson.